Module rok4.style
Provide classes to use a ROK4 style.
The module contains the following classe:
Style- Style descriptor, to convert raster data
Loading a style requires environment variables :
- ROK4_STYLES_DIRECTORY
Classes
class Colour (palette: Dict[~KT, ~VT], style: Style)-
A palette's RGBA colour.
Attributes
value:float- Value to convert to RGBA
red:int- Red value (from 0 to 255)
green:int- Green value (from 0 to 255)
blue:int- Blue value (from 0 to 255)
alpha:int- Alpha value (from 0 to 255)
Constructor method
Args
colour- Colour attributes, according to JSON structure
style- Style object containing the palette's colour to create
Examples
JSON colour section
{ "value": 600, "red": 220, "green": 179, "blue": 99, "alpha": 255 }Raises
MissingAttributeError- Attribute is missing in the content
Exception- Invalid colour's band
Expand source code
class Colour: """A palette's RGBA colour. Attributes: value (float): Value to convert to RGBA red (int): Red value (from 0 to 255) green (int): Green value (from 0 to 255) blue (int): Blue value (from 0 to 255) alpha (int): Alpha value (from 0 to 255) """ def __init__(self, palette: Dict, style: "Style") -> None: """Constructor method Args: colour: Colour attributes, according to JSON structure style: Style object containing the palette's colour to create Examples: JSON colour section { "value": 600, "red": 220, "green": 179, "blue": 99, "alpha": 255 } Raises: MissingAttributeError: Attribute is missing in the content Exception: Invalid colour's band """ try: self.value = palette["value"] self.red = palette["red"] if self.red < 0 or self.red > 255: raise Exception( f"In style '{style.path}', a palette colour band has an invalid value (integer between 0 and 255 expected)" ) self.green = palette["green"] if self.green < 0 or self.green > 255: raise Exception( f"In style '{style.path}', a palette colour band has an invalid value (integer between 0 and 255 expected)" ) self.blue = palette["blue"] if self.blue < 0 or self.blue > 255: raise Exception( f"In style '{style.path}', a palette colour band has an invalid value (integer between 0 and 255 expected)" ) self.alpha = palette["alpha"] if self.alpha < 0 or self.alpha > 255: raise Exception( f"In style '{style.path}', a palette colour band has an invalid value (integer between 0 and 255 expected)" ) except KeyError as e: raise MissingAttributeError(style.path, f"palette.colours[].{e}") except TypeError: raise Exception( f"In style '{style.path}', a palette colour band has an invalid value (integer between 0 and 255 expected)" ) @property def rgba(self) -> Tuple[int]: return (self.red, self.green, self.blue, self.alpha) @property def rgb(self) -> Tuple[int]: return (self.red, self.green, self.blue)Instance variables
prop rgb : Tuple[int]-
Expand source code
@property def rgb(self) -> Tuple[int]: return (self.red, self.green, self.blue) prop rgba : Tuple[int]-
Expand source code
@property def rgba(self) -> Tuple[int]: return (self.red, self.green, self.blue, self.alpha)
class Estompage (estompage: Dict[~KT, ~VT], style: Style)-
A style's estompage parameters.
Attributes
zenith:float- Sun's zenith in degree
azimuth:float- Sun's azimuth in degree
z_factor:int- Slope exaggeration factor
image_nodata:float- Nodata input value
estompage_nodata:float- Nodata estompage value
Constructor method
Args
estompage- Estompage attributes, according to JSON structure
style- Style object containing the estompage to create
Examples
JSON estompage section
{ "zenith": 45, "azimuth": 315, "z_factor": 1 }Raises
MissingAttributeError- Attribute is missing in the content
Expand source code
class Estompage: """A style's estompage parameters. Attributes: zenith (float): Sun's zenith in degree azimuth (float): Sun's azimuth in degree z_factor (int): Slope exaggeration factor image_nodata (float): Nodata input value estompage_nodata (float): Nodata estompage value """ def __init__(self, estompage: Dict, style: "Style") -> None: """Constructor method Args: estompage: Estompage attributes, according to JSON structure style: Style object containing the estompage to create Examples: JSON estompage section { "zenith": 45, "azimuth": 315, "z_factor": 1 } Raises: MissingAttributeError: Attribute is missing in the content """ try: # azimuth et azimuth sont converti en leur complémentaire en radian self.zenith = (90.0 - estompage.get("zenith", 45)) * DEG_TO_RAD self.azimuth = (360.0 - estompage.get("azimuth", 315)) * DEG_TO_RAD self.z_factor = estompage.get("z_factor", 1) self.image_nodata = estompage.get("image_nodata", -99999.0) self.estompage_nodata = estompage.get("estompage_nodata", 0.0) except KeyError as e: raise MissingAttributeError(style.path, f"estompage.{e}") class Exposition (exposition: Dict[~KT, ~VT], style: Style)-
A style's exposition parameters.
Attributes
algo:str- Slope calculation algorithm chosen by the user ("H" for Horn)
min_slope:int- Slope from which exposition is computed
image_nodata:float- Nodata input value
exposition_nodata:float- Nodata exposition value
Constructor method
Args
exposition- Exposition attributes, according to JSON structure
style- Style object containing the exposition to create
Examples
JSON exposition section
{ "algo": "H", "min_slope": 1 }Raises
MissingAttributeError- Attribute is missing in the content
Expand source code
class Exposition: """A style's exposition parameters. Attributes: algo (str): Slope calculation algorithm chosen by the user ("H" for Horn) min_slope (int): Slope from which exposition is computed image_nodata (float): Nodata input value exposition_nodata (float): Nodata exposition value """ def __init__(self, exposition: Dict, style: "Style") -> None: """Constructor method Args: exposition: Exposition attributes, according to JSON structure style: Style object containing the exposition to create Examples: JSON exposition section { "algo": "H", "min_slope": 1 } Raises: MissingAttributeError: Attribute is missing in the content """ try: self.algo = exposition.get("algo", "H") self.min_slope = exposition.get("min_slope", 1.0) * DEG_TO_RAD self.image_nodata = exposition.get("min_slope", -99999) self.exposition_nodata = exposition.get("aspect_nodata", -1) except KeyError as e: raise MissingAttributeError(style.path, f"exposition.{e}") class Legend (legend: Dict[~KT, ~VT], style: Style)-
A style's legend.
Attributes
format:str- Legend image's mime type
url:str- Legend image's url
height:int- Legend image's pixel height
width:int- Legend image's pixel width
min_scale_denominator:int- Minimum scale at which the legend is applicable
max_scale_denominator:int- Maximum scale at which the legend is applicable
Constructor method
Args
legend- Legend attributes, according to JSON structure
style- Style object containing the legend to create
Examples
JSON legend section
{ "format": "image/png", "url": "http://ign.fr", "height": 100, "width": 100, "min_scale_denominator": 0, "max_scale_denominator": 30 }Raises
MissingAttributeError- Attribute is missing in the content
Expand source code
class Legend: """A style's legend. Attributes: format (str): Legend image's mime type url (str): Legend image's url height (int): Legend image's pixel height width (int): Legend image's pixel width min_scale_denominator (int): Minimum scale at which the legend is applicable max_scale_denominator (int): Maximum scale at which the legend is applicable """ def __init__(self, legend: Dict, style: "Style") -> None: """Constructor method Args: legend: Legend attributes, according to JSON structure style: Style object containing the legend to create Examples: JSON legend section { "format": "image/png", "url": "http://ign.fr", "height": 100, "width": 100, "min_scale_denominator": 0, "max_scale_denominator": 30 } Raises: MissingAttributeError: Attribute is missing in the content """ try: self.format = legend["format"] self.url = legend["url"] self.height = legend["height"] self.width = legend["width"] self.min_scale_denominator = legend["min_scale_denominator"] self.max_scale_denominator = legend["max_scale_denominator"] except KeyError as e: raise MissingAttributeError(style.path, f"legend.{e}") class Palette (palette: Dict[~KT, ~VT], style: Style)-
A style's RGBA palette.
Attributes
no_alpha:bool- Colour without alpha band
rgb_continuous:bool- Continuous RGB values ?
alpha_continuous:bool- Continuous alpha values ?
colours:List[Colour]- Palette's colours, input values ascending
Constructor method
Args
palette- Palette attributes, according to JSON structure
style- Style object containing the palette to create
Examples
JSON palette section
{ "no_alpha": false, "rgb_continuous": true, "alpha_continuous": true, "colours": [ { "value": -99999, "red": 255, "green": 255, "blue": 255, "alpha": 0 }, { "value": -99998.1, "red": 255, "green": 255, "blue": 255, "alpha": 0 }, { "value": -99998.0, "red": 255, "green": 0, "blue": 255, "alpha": 255 }, { "value": -501, "red": 255, "green": 0, "blue": 255, "alpha": 255 }, { "value": -500, "red": 1, "green": 29, "blue": 148, "alpha": 255 }, { "value": -15, "red": 19, "green": 42, "blue": 255, "alpha": 255 }, { "value": 0, "red": 67, "green": 105, "blue": 227, "alpha": 255 }, { "value": 0.01, "red": 57, "green": 151, "blue": 105, "alpha": 255 }, { "value": 300, "red": 230, "green": 230, "blue": 128, "alpha": 255 }, { "value": 600, "red": 220, "green": 179, "blue": 99, "alpha": 255 }, { "value": 2000, "red": 162, "green": 100, "blue": 51, "alpha": 255 }, { "value": 2500, "red": 122, "green": 81, "blue": 40, "alpha": 255 }, { "value": 3000, "red": 255, "green": 255, "blue": 255, "alpha": 255 }, { "value": 9000, "red": 255, "green": 255, "blue": 255, "alpha": 255 }, { "value": 9001, "red": 255, "green": 255, "blue": 255, "alpha": 255 } ] }Raises
MissingAttributeError- Attribute is missing in the content
Exception- No colour in the palette or invalid colour
Expand source code
class Palette: """A style's RGBA palette. Attributes: no_alpha (bool): Colour without alpha band rgb_continuous (bool): Continuous RGB values ? alpha_continuous (bool): Continuous alpha values ? colours (List[Colour]): Palette's colours, input values ascending """ def __init__(self, palette: Dict, style: "Style") -> None: """Constructor method Args: palette: Palette attributes, according to JSON structure style: Style object containing the palette to create Examples: JSON palette section { "no_alpha": false, "rgb_continuous": true, "alpha_continuous": true, "colours": [ { "value": -99999, "red": 255, "green": 255, "blue": 255, "alpha": 0 }, { "value": -99998.1, "red": 255, "green": 255, "blue": 255, "alpha": 0 }, { "value": -99998.0, "red": 255, "green": 0, "blue": 255, "alpha": 255 }, { "value": -501, "red": 255, "green": 0, "blue": 255, "alpha": 255 }, { "value": -500, "red": 1, "green": 29, "blue": 148, "alpha": 255 }, { "value": -15, "red": 19, "green": 42, "blue": 255, "alpha": 255 }, { "value": 0, "red": 67, "green": 105, "blue": 227, "alpha": 255 }, { "value": 0.01, "red": 57, "green": 151, "blue": 105, "alpha": 255 }, { "value": 300, "red": 230, "green": 230, "blue": 128, "alpha": 255 }, { "value": 600, "red": 220, "green": 179, "blue": 99, "alpha": 255 }, { "value": 2000, "red": 162, "green": 100, "blue": 51, "alpha": 255 }, { "value": 2500, "red": 122, "green": 81, "blue": 40, "alpha": 255 }, { "value": 3000, "red": 255, "green": 255, "blue": 255, "alpha": 255 }, { "value": 9000, "red": 255, "green": 255, "blue": 255, "alpha": 255 }, { "value": 9001, "red": 255, "green": 255, "blue": 255, "alpha": 255 } ] } Raises: MissingAttributeError: Attribute is missing in the content Exception: No colour in the palette or invalid colour """ try: self.no_alpha = palette["no_alpha"] self.rgb_continuous = palette["rgb_continuous"] self.alpha_continuous = palette["alpha_continuous"] self.colours = [] for colour in palette["colours"]: self.colours.append(Colour(colour, style)) if len(self.colours) >= 2 and self.colours[-1].value <= self.colours[-2].value: raise Exception( f"Style '{style.path}' palette colours hav eto be ordered input value ascending" ) if len(self.colours) == 0: raise Exception(f"Style '{style.path}' palette has no colour") except KeyError as e: raise MissingAttributeError(style.path, f"palette.{e}") def convert(self, value: float) -> Tuple[int]: # Les couleurs dans la palette sont rangées par valeur croissante # On commence par gérer les cas où la valeur est en dehors de la palette if value <= self.colours[0].value: if self.no_alpha: return self.colours[0].rgb else: return self.colours[0].rgba if value >= self.colours[-1].value: if self.no_alpha: return self.colours[-1].rgb else: return self.colours[-1].rgba # On va maintenant chercher les deux couleurs entre lesquelles la valeur est for i in range(1, len(self.colours)): if self.colours[i].value < value: continue # on est sur la première couleur de valeur supérieure colour_inf = self.colours[i - 1] colour_sup = self.colours[i] break ratio = (value - colour_inf.value) / (colour_sup.value - colour_inf.value) if self.rgb_continuous: pixel = ( colour_inf.red + ratio * (colour_sup.red - colour_inf.red), colour_inf.green + ratio * (colour_sup.green - colour_inf.green), colour_inf.blue + ratio * (colour_sup.blue - colour_inf.blue), ) else: pixel = (colour_inf.red, colour_inf.green, colour_inf.blue) if self.no_alpha: return pixel else: if self.alpha_continuous: return pixel + (colour_inf.alpha + ratio * (colour_sup.alpha - colour_inf.alpha),) else: return pixel + (colour_inf.alpha,)Methods
def convert(self, value: float) ‑> Tuple[int]
class Slope (slope: Dict[~KT, ~VT], style: Style)-
A style's slope parameters.
Attributes
algo:str- Slope calculation algorithm chosen by the user ("H" for Horn)
unit:str- Slope unit
image_nodata:float- Nodata input value
slope_nodata:float- Nodata slope value
slope_max:float- Maximum value for the slope
Constructor method
Args
slope- Slope attributes, according to JSON structure
style- Style object containing the slope to create
Examples
JSON pente section
{ "algo": "H", "unit": "degree", "image_nodata": -99999, "slope_nodata": 91, "slope_max": 90 }Raises
MissingAttributeError- Attribute is missing in the content
Expand source code
class Slope: """A style's slope parameters. Attributes: algo (str): Slope calculation algorithm chosen by the user ("H" for Horn) unit (str): Slope unit image_nodata (float): Nodata input value slope_nodata (float): Nodata slope value slope_max (float): Maximum value for the slope """ def __init__(self, slope: Dict, style: "Style") -> None: """Constructor method Args: slope: Slope attributes, according to JSON structure style: Style object containing the slope to create Examples: JSON pente section { "algo": "H", "unit": "degree", "image_nodata": -99999, "slope_nodata": 91, "slope_max": 90 } Raises: MissingAttributeError: Attribute is missing in the content """ try: self.algo = slope.get("algo", "H") self.unit = slope.get("unit", "degree") self.image_nodata = slope.get("image_nodata", -99999) self.slope_nodata = slope.get("slope_nodata", 0) self.slope_max = slope.get("slope_max", 90) except KeyError as e: raise MissingAttributeError(style.path, f"pente.{e}") class Style (id: str)-
A raster data style
Attributes
path:str- TMS origin path (JSON)
id:str- Style's technical identifier
identifier:str- Style's public identifier
title:str- Style's title
abstract:str- Style's abstract
keywords:List[str]- Style's keywords
legend:Legend- Style's legend
palette:Palette- Style's palette, optionnal
estompage:Estompage- Style's estompage parameters, optionnal
slope:Slope- Style's slope parameters, optionnal
exposition:Exposition- Style's exposition parameters, optionnal
Constructor method
Style's directory is defined with environment variable ROK4_STYLES_DIRECTORY. Provided id is used as file/object name, with pr without JSON extension
Args
path- Style's id
Raises
MissingEnvironmentError- Missing object storage informations
StorageError- Storage read issue
FileNotFoundError- Style file or object does not exist, with or without extension
FormatError- Provided path is not a well formed JSON
MissingAttributeError- Attribute is missing in the content
Exception- No colour in the palette or invalid colour
Expand source code
class Style: """A raster data style Attributes: path (str): TMS origin path (JSON) id (str): Style's technical identifier identifier (str): Style's public identifier title (str): Style's title abstract (str): Style's abstract keywords (List[str]): Style's keywords legend (Legend): Style's legend palette (Palette): Style's palette, optionnal estompage (Estompage): Style's estompage parameters, optionnal slope (Slope): Style's slope parameters, optionnal exposition (Exposition): Style's exposition parameters, optionnal """ def __init__(self, id: str) -> None: """Constructor method Style's directory is defined with environment variable ROK4_STYLES_DIRECTORY. Provided id is used as file/object name, with pr without JSON extension Args: path: Style's id Raises: MissingEnvironmentError: Missing object storage informations StorageError: Storage read issue FileNotFoundError: Style file or object does not exist, with or without extension FormatError: Provided path is not a well formed JSON MissingAttributeError: Attribute is missing in the content Exception: No colour in the palette or invalid colour """ self.id = id try: self.path = os.path.join(os.environ["ROK4_STYLES_DIRECTORY"], f"{self.id}") if not exists(self.path): self.path = os.path.join(os.environ["ROK4_STYLES_DIRECTORY"], f"{self.id}.json") if not exists(self.path): raise FileNotFoundError(f"{self.path}, even without extension") except KeyError as e: raise MissingEnvironmentError(e) try: data = json.loads(get_data_str(self.path)) self.identifier = data["identifier"] self.title = data["title"] self.abstract = data["abstract"] self.keywords = data["keywords"] self.legend = Legend(data["legend"], self) if "palette" in data: self.palette = Palette(data["palette"], self) else: self.palette = None if "estompage" in data: self.estompage = Estompage(data["estompage"], self) else: self.estompage = None if "pente" in data: self.slope = Slope(data["pente"], self) else: self.slope = None if "exposition" in data: self.exposition = Exposition(data["exposition"], self) else: self.exposition = None except JSONDecodeError as e: raise FormatError("JSON", self.path, e) except KeyError as e: raise MissingAttributeError(self.path, e) @property def bands(self) -> int: """Bands count after style application Returns: int: Bands count after style application, None if style is identity """ if self.palette is not None: if self.palette.no_alpha: return 3 else: return 4 elif self.estompage is not None or self.exposition is not None or self.slope is not None: return 1 else: return None @property def format(self) -> ColorFormat: """Bands format after style application Returns: ColorFormat: Bands format after style application, None if style is identity """ if self.palette is not None: return ColorFormat.UINT8 elif self.estompage is not None or self.exposition is not None or self.slope is not None: return ColorFormat.FLOAT32 else: return None @property def input_nodata(self) -> float: """Input nodata value Returns: float: Input nodata value, None if style is identity """ if self.estompage is not None: return self.estompage.image_nodata elif self.exposition is not None: return self.exposition.image_nodata elif self.slope is not None: return self.slope.image_nodata elif self.palette is not None: return self.palette.colours[0].value else: return None @property def is_identity(self) -> bool: """Is style identity Returns: bool: Is style identity """ return ( self.estompage is None and self.exposition is None and self.slope is None and self.palette is None )Instance variables
prop bands : int-
Bands count after style application
Returns
int- Bands count after style application, None if style is identity
Expand source code
@property def bands(self) -> int: """Bands count after style application Returns: int: Bands count after style application, None if style is identity """ if self.palette is not None: if self.palette.no_alpha: return 3 else: return 4 elif self.estompage is not None or self.exposition is not None or self.slope is not None: return 1 else: return None prop format : ColorFormat-
Bands format after style application
Returns
ColorFormat- Bands format after style application, None if style is identity
Expand source code
@property def format(self) -> ColorFormat: """Bands format after style application Returns: ColorFormat: Bands format after style application, None if style is identity """ if self.palette is not None: return ColorFormat.UINT8 elif self.estompage is not None or self.exposition is not None or self.slope is not None: return ColorFormat.FLOAT32 else: return None prop input_nodata : float-
Input nodata value
Returns
float- Input nodata value, None if style is identity
Expand source code
@property def input_nodata(self) -> float: """Input nodata value Returns: float: Input nodata value, None if style is identity """ if self.estompage is not None: return self.estompage.image_nodata elif self.exposition is not None: return self.exposition.image_nodata elif self.slope is not None: return self.slope.image_nodata elif self.palette is not None: return self.palette.colours[0].value else: return None prop is_identity : bool-
Is style identity
Returns
bool- Is style identity
Expand source code
@property def is_identity(self) -> bool: """Is style identity Returns: bool: Is style identity """ return ( self.estompage is None and self.exposition is None and self.slope is None and self.palette is None )